First, make the dipping sauce. Crush the garlic, coriander and chilli using a pestle and mortar. (If you don’t have one, just finely chop.) Pound in the sugar until dissolved, then add the lime juice and fish sauce. It should taste sweet, salty and spicy.
To make the spice mix, toast the Sichuan and black peppercorns in a frying pan over a medium heat for 1 min or until fragrant. Finely grind in a spice mill or using a pestle and mortar, then add the salt and chilli flakes and mix together. Transfer to a bowl.
Combine the spice mix with the cornflour. Heat 7.5cm of oil in a large wok or deep heavy-based saucepan. You can test the temperature by frying a small piece of bread – it should sizzle instantly and take 20 secs to turn golden. Toss the prawns with the spice mix, shake off the excess and deep-fry, in batches, for 1-2 mins or until crisp at the edges and starting to curl. Remove with a slotted spoon, drain on a baking tray lined with kitchen paper and keep warm while you cook the remaining prawns. Scatter over the pea shoots or salad leaves, if you like, and serve with the dipping sauce.
Recipe from Good Food magazine, February 2013